What is The Fight then?

Long time lurker, first time poster here. I know people have a bunch of opinions right now and frankly I can listen to Act 3 and pause by The Good Doctor Pt.2 as right now, without the notes, The Fate of Thomas Light kinda does nothing to me (I was on camp "Light is dead since track X", so the final track being his death is basically taking from the previous track, where I already thought he died taking Wily with him).

My question is: what is The Fight then? An epilogue released years ahead of the album? A parallel universe thing? A discarded end that they liked (me too) and thought to release as a single?

I've read the many, many times they said TFoTL is the last song of the implied last album and I can accept it being an extra "HE'S DEAD, SERIOUSLY" track, but while The Fight does fit after TFoTL, if that is supposed to be the case why they wouldn't add to the album?

Unless ... (Nah, it's done)